Boat hull

ABSTRACT

A boat body or hull, especially suitable for racing type sailboats, has a thin outer plastic shell, a plastic inner or false bottom in the shell and secured around its periphery to the shell and a plastic deck covering the shell composed of spaced top and bottom layers. The spaces between the shell and inner bottom and between the top and bottom layers of the deck are filled with a hard foam plastic material itimately bonded by fibrous laminations to the walls defining the spaces with fibers of the laminations embedded in the foam.

United States Patent 11 1 Stoeberl BOAT HULL [76] Inventor: I-Ielmut Stoeberl, 8201 Eggstaett-Bachham, Germany [22] Filed: Jan. 12, 1973 21 Appl. No.: 323,319

[30] Foreign Application Priority Data Jan. 12, 1972 Germany 2201319 [52] U.S. Cl. 9/6 [51] Int. Cl B63b 5/24 [58] Field of Search 9/6 [56] References Cited UNITED STATES PATENTS 3,291,088 12/1966 3,531,809 10/1970 3,591,443 7/1971 3,747,550 7/1973 Stoeberl 9/6 1451 Oct. 15, 1974 FOREIGN PATENTS OR APPLICATIONS 1,435,581 6/1965 France 9/6 Primary Examiner-Trygve M. Blix Assistant Examiner-Stuart M. Goldstein Attorney, Agent, or FirmI-Iill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT A boat body or hull, especially suitable for racing type sailboats, has a thin outer plastic shell, a plastic inner or false bottom in the shell and secured around its periphery to the shell and a plastic deck covering the shell composed of spaced top and bottom layers; The spaces between the shell and inner bottom and between the top and bottom layers of the deck are filled with a hard foam plastic material itimately bonded by fibrous laminations to the walls defining the spaces with fibers of the laminations embedded in the foam.

13 Claims, 42 Drawing Figures PATENTED 9U 151974 3.840 926 SHEET 03 0F 16 PATENTED BET 5W4 3. 840,926

SHEET 01H]? 16 PATENIEU a 3.840.928

sum near 16 BOAT HULL FIELD OF THE INVENTION This invention relates to hollow foam-filled plastic boat hulls and particularly to glass fiber reinforced plastic boat bodies having hard plastic foam-filled chambers with the foam integrally bonded to the plastic walls defining the boat shell, a false bottom for the shell, and top and bottom deck layers, through the intermediary of laminations having fibers embedded in the foam.

PRIOR ART Foam-filled hollow boat shells are known in the art as for example, in the US. Letters Patents Nos. 2,909,791; 3,531,809; and 3,433,470, French Pat. No. 1,443,919 and British Pat. No. 931,244. Provisions of longitudinal and transverse stringers between inner and outer shells of boat hulls are known for example, in

US Letters Patent No. 2,956,292; British Pat. No. 966,508, and German Pat. No. 940,787. These prior art disclosures, however, deal with motorboats and their constructions are not suitable for racing-type sailboats where both the keel and the deck must provide maximum stiffness and minimum weight. In plastic sailboat bodies it is essential that the hull will not warp or bend under stress, and that the deck and hull be sealed against leakage.

SUMMARY OF THE INVENTION the periphery of the boat shell. The spaces between the shell and false bottom and between the top and bottom deck sheets are filled with a-hardened plastic foam and this foam is integrated with the plastic sheets forming the spaces by fiber material bonded to the plastic shell, false bottom and deck sheets and having fibers embed ded in the hard foam filling the spaces between the molded plastic parts. The fibrous material may be woven plastic sheets cemented to the molded plastic parts and may be provided in multiple layers to also act as reinforcements at high stress points in the constructron.

The provision of the false bottom in the boat shell makes possible the use of a very thin shell thereby providing an important weight reduction feature especially for racing-type sailboats.

Where a multi-layer lamination is provided between the foam and molded plastic boat parts, the inner lamiations preferably have extending fibers, loops and the like embedded in the foam material.

The false bottom provided in the boat body constructions of this invention eliminates the heretofore required necessity for longitudinal and transverse stringers and the false bottom together with the deck provide ample reinforcement for even a very thin boat shell sufficient to resist warping and binding even under severe stress. However, reinforcements such as a mast foot, a forestay rail, a rudder post, and the like can be provided.

It is, therefore, an object of this invention to provide plastic boat hulls with hard foam fillings integrally bonded to the plastic by means of laminated material secured to the plastic and having fibers embedded in the foam.

Another object of the invention is to provide a lightweight foam filled plastic boat hull with a false bottom effective to rigidify even a very thin boat shell against warpage and bending.

Another object of the invention is to provide a sailboat deck and hull construction composed of molded plastic sheets with spaces therebetween filled with hard plastic foam integrally bonded to theplastic sheets.

A specific object of the invention is to provide a sailboat body having a fiber reinforced thin molded plastic shell, a false bottom in the shell secured around its periphery to the shell and providing a chamber between the shell and bottom and a deck secured around its periphery to the top of the shell having top and bottom molded plastic sheets with a space therebetween, and hard foam plasticmaterial filling the spaces between the shell and false bottom and between the deck sheets and integrally bonded to the plastic material defining the spaces that are filled by the foam.

The invention will be explained in greater details hereinafter, with further features, by means of examples of embodiment which are illustrated in the accompanying drawings, wherein:

FIGS. la to 10 show diagrammatic longitudinal and cross-sections through the boat hull according to the invention or parts thereof,

FIGS. 1p to y la show, diagrammatic cross-sections through the connection between deck and hull,

FIGS. 2a to 2e show diagrammatic partial crosssections through the mould serving'for the production of the boat hull according to the invention,

FIG. 3 shows a partial cross-section through the inner mould half, FIG. 4 shows a diagrammatic partial cross-section through the closed production mould,

FIGS. 5a to 5f show cross-sections through further examples of embodiment of the production mould, 9

FIGS. 6a, 6b, 60 show longitudinal and cross-sections through the mould serving for the production of the deck,

FIGS. 7, 7a 7e show different forms of embodiment of the multilayer laminated insert used for the production of the hull and the deck.

In the description which follows, references to the accompanying drawings will be used as follows:

7 second gel coating -Continued vacuum bag sealing rib sealing lip sealing lip foam material mould half (outer or lower) through-passing bores mould inner shell mould outer shell support core mould flange inner mould flange outer mould half (inner or upper) through-passing bores mould inner shell mould outer shell support core mould flange inner mould flange outer suction connection seal suction connection vent suction passage cross passage cross passages in vacuum bag wedge-shaped sealing groove cavity suction connection vacuum bag sealing strip sealing strip bead foam material charging pipe bore for foam charging pipe sealing cone securing ribs interlayer aperture mould separation line shell connector connection piece to foam generator introducing centring pyramid mould inner space keel fitting centring wedge face reinforcing laminate reinforcing laminate lst position reinforcing laminate 2nd position reinforcing laminate 3rd position junction point laminate strip junction point of the multilayer laminated insert upper marginal zone inner upper marginal zone outer bilge channel keel case insert connection point deck cockpit aperture reinforced edge rudder aperture rudder post collar mast aperture reinforced edge spinnaker aperture bow stern mould upper part mould lower part connecting screws centring pyramid mould part mould part tension band tension band lock centrin g slope overgrasping centring and retaining flange flange inner layer flange outer layer flange mould half outer frame lower frame upper reinforcing inserts in the mould parts deflector support cores peripheral stiffening frame inner mould pan peripheral stiffening frame outer mould part intermediate support laminate connecting screw distance tube boat hull boat shell deck stern bow keel fin inner bottom side parts of inner bottom spinnaker funnel Continued 108 forestay guide 109 spinnaker guide 1 l0 connection point 1 1 1 mast aperture 1 l2 mast aperture collar 1 13 mast aperture bead 1 14 sheet guide l 15 oblique surface 1 16 support board 1 l7 sheet clip l 18 cockpit aperture 119 cockpit head 1 19a cockpit reinforcement 120 oblique surface 121 deck upper layer l2la deck lower layer 122 rudder post tube 123 head l24 collar 125 bearing bush 126 retraction 127 connection point 128 bush under 129 middle carrier piece 130 bottom 1 31 reinforcing laminate 13 la reinforcing laminate 2nd position 146 stem inner bottom 147 stern turnover 148 frame 149 reinforcement rudder post bearing 150 synthetic plastics intermediate layer 151 synthetic plastics connecting layer 152 tube widening 153 centre carrier piece transition 154 bearing bush 155 deck fitting 156 separated piece 157 oblique surface 158 forestay rail 159 forestay bolt 160 deck section 161 shell connector 162 edge connector 163 boat shell retaining web outer 164 boat shell retaining web inner 165 deck retaining web outer 166 deck edge 167 slot 168 connecting layer 169 fitting for spinnaker collar [70 spinnaker collar 171 funnel 172 plane of separation 173 how fitting 174 how eye 175 securing rivet 176 bilge channel 177 retraction of the inner bottom 178 retraction of the boat shell X79 opening for bilge valve I80 connecting layer I81 fin retaining fitting 182 retaining fitting case 1 8 3a reinforcing laminate 183b reinforcing laminate 183c reinforcing laminate 184 connecting layer.

The boat hull according to the invention, the method steps serving for the production of this hull and necessary or suitable devices will be described in detail hereinafter, the construction and assembly of the hull, consisting of the boat shell 101 and the deck 102 being described in detail in connection with FIGS. to la.

As represented in a diagrammatic longitudinal section in FIG. 1a, the boat hull 100 consists of a boat shell 101 and a deck 102. The boat shell 101 has a bow 104 which is shaped approximately in the form of a spoon bow, and an after part 103 of which the stem is formed to slope in forwards and forms a rearward sharp breakaway edge 143. The hull is constructed essentially from a boat shell 101 and an inner bottom 106 arranged in the internal space of the boat shell 101. This inner bottom 106 contains the essential carrying elements of the boat hull and is accordingly provided with a central carrier piece 129, which is hereinafter merely illustrated and described as simple trapezoidal longitudinal profiling. However it is foreseen to make this central carrier piece with single or multiple articulation and possibly profiled to protrude inwards into the boat internal space and/or also downwards into the interspace between inner bottom 106 and boat shell 101. This profiling can continue into the lateral zones 106a of the inner bottom 106 in the longitudinal and/or transverse direction, so that correspondingly according to the invention the essential carrying and shape-maintaining component is constituted by the inner bottom 106, and not as usual by the outer shell 101.

For the stiffening of the inner bottom 106 and for the connection with the actual boat shell 101, which is formed essentially as open, unstiffened shell, there serves a foam material filling 9, which consists essentially of hard foam material and is charged, as will be described later, into the mould cavity between the inner bottom 106 and the boat shell 101, bonding on all sides.

Due to this measure, without special stiffenings, stringers, spar elements, clamps or the like, an extraordinarily longitudinally and transversely rigidly formed boat hull is achieved, without the necessity for this purpose of extensive, difficulty produced and expensive moulded-on laminations, spar elements or transverse bulkhead formations.

As represented in Flg. 1a, in the boat shell 101 the inner bottom 106 is advantageously so arranged that it comes to lie approximately parallel with the floating water line, but slightly above it, the central carrier piece 129 lying approximately in the longitudinal axis of the carrying inner bottom 106 so that it may be regarded as a highly placed keel beam, providing support and formed not as usual on the boat skin 101 but on the inner bottom 106. Moreover from FIG. 1a it may be seen that one or more bow reinforcing laminate layers 141, 141a are formed on the boat shell 101 in the region of the bow 104, which reinforce the especially endangered zone of the boat shell 101 in the region of the bow.

Likewise, as shown in cross-section in FIG. lb, one or more formed-out portions are provided in the form of a fitting receiving part 132 for the reception of a keel fin 105 in the middle region. This retaining fitting 132 serves to receive a centring piece 133 which is formed on the keel fin 105 in conformity with the retaining fitting 132, the centring piece 133 merging, by way of a transition piece 137 of hydrodynamically favourable shape into the fin surface 134, in the lower region of which a ballast 135 is arranged. The keel fin 105 is separately produced as shell component and is especially moulded in two-shell manner with moulding-in of the ballast 135 in appropriate mould halves, while a reinforcing lamination 136 can be provided in the zone of the keel fin leading edge, and also in the zone of the ballast 135, and furthermore an appropriate transition laminated reinforcement 137 can be provided in the region of the centring piece 133 and also the entire cavity between the shell parts of the keel fin 105 is filled out with hard foam material.

For the securing of the keel fin 105 to the boat hull keel securing bolts 144 are provided in the upper region of the keel fin or of the centring piece 133, which bolts are introducible approximately parallel upwards into the corresponding retaining fitting 132 of the hull or into the corresponding aperture or receiving part of the middle carrier piece 129 of the inner bottom 106, engage through corresponding bores into the internal space of the hull and are made fast there by eyes, nuts or the like. The keel securing bolts 144 are laminated by means of keel bolt lugs 145 fitted on them to one or the other or both shells of the keel fin 105, corresponding reinforcing laminates or corresponding synthetic plastics material applications being provided in the region of the centring piece 133 of the keel fin.

The retaining fitting 132 can be made approximately pyramid-shaped in its cross-section and approximately elliptical in its horizontal cross-section, and can be formedwith its forward retaining fitting 138 and also with its rearward retaining fitting so that a certain keel offset is possible by corresponding approximately spherical or arcuate formation of the individual surfaces. Here it is possible to shift the keel fin 105 by a small amount, as regards its centre of weight gravity and centre of lateral surface gravity in relation to the actual hull, in which case any occurring interspace between the retaining fitting 132 formed in the boat shell 101 can be effected by introduction of a corresponding connection means, for example application of synthetic plastics material, both for securing and for difference compensation.

The middle carrier piece 129 of the inner bottom 106 is drawn up in the forward region, that is in the region of the bow 104, approximately in conformity with the curvature of the bow, and is provided in the region of the forestay attachment with a forestay reinforcing laminate 140, which can be made in one or more layers, and a forestay rail 142 can be connected with the forestay reinforcing laminate 140 or 140a. Extending forward in this region, but especially extending over the entire region of of the middle carrier piece 129, a reinforcing laminate layer 131 is provided in the region of the middle carrier piece 129, which layer can be provided either locally or throughout with further reinforcing laminate layers 131a in the region of the rudder post, in the region of the retaining fitting 132 of the keel fin and especially in the region of the mast foot 139.

The actual bottom 130, visible to the crew, of the inner bottom can be lowered more or less in relation to the middle carrier piece 129, especially made oblique in roof form, and extends gradually upwards into the boat shell edge, towards the boat shell 1, at the side parts, as may be seen from FIG. ll. In the after region of the hull a rudder post tube 122 is arranged in which the actual rudder post is mounted. In the region of the lower passage of the rudder post through the boat shell 101 here the middle carrier piece 129 or the inner bottom 106 is lowered, by formation of a cup-shaped re- 

1. A plastic boat body which comprises a molded plastic boat shell, an inner bottom shell in said boat shell and secured around its periphery to the boat shell, said boat shell and inner bottom shell providing a chamber therebetween, an insitu cast hard foam plastic core filling said chamber in full conformity therewith, fiber lamination sheets integrally bonded to and covering the faces of the boat shell and inner bottom defining said chamber, plastic from the boat shell and inner bottom shell being embedded in interstices of said fiber lamination sheets, and fibers of said laminations sheet surrounded by the cast foam plastic core and embedded therein in locked relation therewith to integrally bond the foam plastic core to the boat shell and inner bottom.
 2. The boat body of claim 1 including a deck covering the shell composed of spaced top and bottom molded plastic sheets, hard plastic foam filling the space between said sheets in full conformity therewith and laminations bonded to the sheets having fibers embedded in the plastic foam.
 3. The boat body of claim 1 wherein the shell is saucer-shaped with rounded sides extending above the inner bottom, and the inner bottom has a flat bottom portion parallel to and above the water line of the boat.
 4. The boat body of claim 2 wherein the sides of the shell extend to the deck and the deck is spaced above the inner bottom.
 5. The boat body of claim 1 including multi-layer lamination inserts surrounding the foam with the fibers of the laminations embedded in the foam and cemented to the inner bottom and shell.
 6. The boat body of claim 2 wherein the fiberous material is a woven lamination having threads extending therefrom into the plastic foam.
 7. The boat body of claim 1 wherein the shell has a keel box recess in the bottom thereof receiving therein the upper end of a keel.
 8. The boat body of claim 1 including additional fibrous lamination layers positioned at points of stress of the shell to reinforce the construction.
 9. The boat body of claim 2 including a rudder post tube anchored in the deck, the inner bottom and the shell.
 10. The boat body of claim 1 including a deck overlying the shell and secured around the periphery thereto through a water-tight joint.
 11. The boat body of claim 1 including a mast foot extending transversely across the inner bottom and secured at its ends to the shell.
 12. The boat body of claim 1 wherein plastic from the boat shell and inner bottom shell is pulled into interstices of the fiber lamination sheets and interlock the sheeets with the shells and the sheets have threads extending therefrom which are embedded into the hard foam.
 13. The boat body of claim 12 wherein at least one of the fiber lamination sheets has an underlying fibrous layer and threads of the underlying layer in the form of loops are pulled into the overlying layer. 